# Equation in Latex

I am new in the latex. I am trying to write an equation in the latex. I have searched a lot of question regarding equations and tried all possible solutions but I m not getting what I want. I also used different tools but still not getting my equation. Kindly help me. • Welcome to TeX.SX! Maybe you can get some inspirations in this tutorial or this post. – Ruixi Zhang Sep 20 '18 at 17:59
• Use the cases environment. See this example. – Alan Sep 20 '18 at 18:09
• Or dcases from mathtools. I guess that the main problem is that no one really wants to type up things from a screen shot. So you may get an answer more quickly if you post what you have tried in such a way that one could just copy and paste these lengthy texts. – marmot Sep 20 '18 at 18:11
• Your definitions are weird. I think the condition of speed on the first line is redundant or non required, because your 3rd line says that the value is 1 regardless of the speed condition. Check the cases environment, and you might need some alignment tips. How do you want to label it? A single number for the whole equation? A number plus a letter per branch? Finally, check how to put regular text within an equation. It avoids having the if condition typeset as the product of i*f. – phollox Sep 20 '18 at 18:14
• @marmot yes I agree with you that I have to show my code but that code doesn't give a sense. I know how to add other expressions but the problem is am not getting how to start it. Next time I will be careful. – Fizzah Sep 20 '18 at 19:01

I agree with phollox that logically this does not make too much sense, nor do I now if SVP is a product of 3 variables or some expression. Nevertheless, the following my give you a start.

\documentclass[fleqn]{article}
\usepackage{mathtools}
\usepackage{siunitx}
\begin{document}
$AD=\begin{dcases} 1 & \text{if}~\left(\left(\frac{AC}{4G}+\frac{\text{Noise}}{\si{400\decibel}}\right)\right) \ge\text{Accident threshold}\wedge\left(\text{Speed}\ge\si{24\kilo\meter\per\hour}\right) \\ 1 & \text{if}~\left(\left(\frac{AC}{4G}+\frac{\text{Noise}}{\si{400\decibel}} +\frac{SVP}{2.06}\right)\right) \ge\text{Low speed threshold}\\ 1 & \text{if}~\left(\left(\frac{AC}{4G}+\frac{\text{Noise}}{\si{400\decibel}} \right)\right) \ge\text{Accident threshold}\\ 0 &\text{otherwise} \end{dcases}$
\end{document} • Thank you very much. It is a perfect answer that helps me a lot. – Fizzah Sep 21 '18 at 11:21